package PTA2.ti23;

import java.util.Scanner;

/**
 * @author Lenovo
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int m = scanner.nextInt();
        int s = scanner.nextInt();
        double d= scanner.nextDouble();
        double hour = (double) (m * 60 + s) /3600;
        double mile=d/1.6;
        double speed=mile/hour;
        System.out.printf("%.2f",speed);
    }
}
